Micro Motor Community

Converting 2.5inch drone to 3 inch?



so i thought about converting my quad to a bigger frame so i can use 3025 gemfan props.
for now im using the gemfans 2540 along with 1105 6000kv motors, is it a major improvement to go from 2540X3 props to 3025X2 props? btw i dont plan to use 3 bladed 3 inch because i only have 450 3s batts so i need something efficiant.
got the idea after watching this guys 3 inch racer: https://www.youtube.com/watch?v=xNe4t1xmNJI


It depends on the build. I’m using 1106 4500 KV motors on 3S 450mah. Personally, I prefer the 3 blade props because it makes my quadcopter feel more locked in. I use the uSmile 112mm frame in the link in my video. It can fit a 20x20 FC and 3 inch props.

For comparison.

Here’s a video with gemfan 3 inch 2 blade props:

And here is a video with gemfan 3 inch 3 blade props:


of course 3 bladed prop will have more control than a 2 bladed prop of the same size, but will a 2,5inch 3 bladed prop will be better than a 3 inch 2 bladed? the 3 inch should have more power and efficiency for sure, i wont use 3 inch 3 bladed because motors will overheat and i like decent flytimes
so the question is 2540X3 or 3025X2
also that frame looks really interesting, 112mm that fits 3 inch!
i originally wanted to go for this
frame or that frame
do you recommend the uSmile 112mm?


I don’t have any 2.5inch props.

Normally, if the motor can handle it, larger props mean more efficiency and more blades mean decreased efficiency, a bit more thrust, and increased control. You’d also be decreasing in pitch when going from your 2.5 inch to 3 inch props, which decrease thrust. All in all, I think it might be roughly equal in your case.

Those other frames look interesting. About the same weight at the uSmile frame, though the uSmile frame has 3mm bottom plate which is super strong. Had some pretty bad crashes into pavement and it didn’t break (knock on wood)! So far I do like the uSmile 112mm frame, but it’s up to you.


the Usmile doesnt offer alot of camera protection so it kinda turned me off
at first i liked the qav-r but the lack of spacers im the middle and battery on top makes me think the top plate would break very easily meanwhile the atlas 130mm frame looks almost too perfect, strong, decent space and camera protection


Yeah that’s why I 3D printed a camera guard and slightly better mount for it here: https://www.thingiverse.com/thing:2763094


The Gemfan 3025 props run really nicely on an 1105 6000kV motor, this is what I use on my Komori with a 3s 450mah battery. You’ll get more efficiency and will use the middle of the powerband more than the upper range. Batteries will last longer too all other things being equal.

Here is my komori build and details:


@monkeymagic Man that’s a very nice frame. What’s the thickness of the base plate and side plates?

My 3 inch has a slightly heavier frame, but it’s survived a crash from 50ft onto pavement with no delamination, just a slight chip on one of the arms. Better for me, since it was my first outdoor brushless build, though now I’m all about going as light as possible! :smiley:


that frame looks really really good the best one ive seen but… price + shipping cost double the cost of the atlas 130mm frame so i think ill take the atlas frame which should be fine.
btw do you like those 1105 motors(hglrc) ? i have 7 of them and from my experience they break/ stop working really fast and even might come not working straight out of the box…
im thinking of replacing them with the bbb 1105 motors they cost 18$ and should have much better quality


It’s 2mm which is why it has the sidebraces - designed to be very lightweight. I would not want to drop it from 50ft! That X3 you have looks good and solid. A working heavy drone is better than a broken light one!


Yeah it is spendy. Check out the flyfox / frog frame which you can get in 2.5 and 3" as well, I think they have on Banggood and MyRCmart. It is very light.

I’m liking the 1105 HGLRC motors but haven’t put as many packs in at this stage so can’t comment on durability. I can say that they worked well out of the box and haven’t had any issues in about 30 flights on 2s or 3s. $18 is a lot for an 1103 motor. Check out the RCX 1304 - they sound really good depending on what you are trying to achieve.


Haha! I think I may have gotten lucky on that one!


yea i already saw that frame but the cons are its 135mm(kinda big) and to fit vtx and receiver on that frame im pretty sure ill have to mount them on fc which wont work well on mine cause it has a icm 20608 gyro and from my experience it will mess it up, flyfox also have this frame
which uses 25mm spacers so i could mount vtx to the top without it touching anything. + its only 120mm and i really prefer things to be smaller
btw the bbb 1105 motors cost 18$ for 2 pcs, with a coupon that goes down to 8$ a motor which is a really good price


$18 for 2 motors makes more sense, $16 even better :smiley:

BBB make excellent 2207 motors under their own brand and others, would be good to hear how the little ones go.


already have the 2207 for my 5 inch, ill give the hglrc 1105 1 more chance and ill get the bbb ones if they fail again, ill do a review if i get them


The 3B and HGLRC motors look like the same motor to me, except for the base. The drawings are the same (for external dimensions). I bought some HGLRC HF1104 motors recently, they seem to run smooth and quiet (no bearing noise).